Two things you need to take care of :-
Create Appropriate Permissions Levels and Groups
Make permission level say "Generic Edit" for Edit access which includes - Add , Edit , View no delete,no approve. Make another permission level say "Generic Add" which includes - Add , no edit, Read , no delete , no approve.
Create groups for Managers and Employees and give them read access at the site level. At the list level give the Managers group "Generic Edit" rights and the Employees group "Generic Add".
Create a list view.
Create a list view for all employees and make it as the default view. On the view creation page , Select filter options and the field to filter should be "created by" and enter the value as "[me]" without the quotes. This will only show items that were created by the currently logged in user and not all the items in the list.
To show the managers all items in the list , create a page in the pages library and add the list to a webpart zone. Here you can create a view that shows all items and this view remains specific to the webpart. Grant the managers group read access on this page through 'manage permissions'.
This way , you can set two different views of a single list for two groups without using a workflow.